Current caterpillar track devices have some significant defects, one of which is that, when meeting a vertical wall obstacle, a caterpillar track is jacked up in a gap thereof between two supporting wheels by the obstacle to semi-enclose the obstacle. The jacking-up of the caterpillar track caused by the obstacle makes the caterpillar track protrude upwards. The tension of the caterpillar track is transmitted onto tensioning wheels, causing change of the tension and hence the increasing of power consumption. Another major defect is that, when the caterpillar track is jacked up by the obstacle and protrude upwards, a plurality of supporting wheels which roll on the caterpillar track will start to climb in turn over the obstacle from the lowest position of the obstacle. The number of times of the caterpillar track's climbing over the obstacle depends on the number of the supporting wheels climbing over the obstacle, and each climbing of the supporting wheels over the obstacle consumes approximate additional power. In a traditional caterpillar track device, if the thickness of a caterpillar track such as a rubber caterpillar track is increased to disperse the ground stress onto more supporting wheels, the winding stress is also increased correspondingly during large-curvature revolution. If the thickness of a rigid caterpillar track is increased, the change of tension is also increased correspondingly during large-curvature revolution. In view of the effect of dispersing the ground stress of the traditional caterpillar device, the transverse stress of the rigid caterpillar track is basically and wonderfully dispersed, whilst the dispersion of the longitudinal stress is insufficient. However, neither the transverse stress nor the longitudinal stress of the rubber caterpillar track is wonderful y dispersed, the stress of the obstacle causes a rubber track or caterpillar track between two supporting wheels to be upwards arched and curved, supporting wheels at the rear need to climb over the arched rubber track or caterpillar track one by one, and consequently the power consumption of each supporting wheel is increased.
For this reason, the inventor ever invented a deformable wheel which was patented as Chinese patent No. 99114647.6. In this patent, an axle housing is adopted for installing supporting wheels and track fixing wheels. Vertical supporting wheels which are linearly distributed on the axle housing are adopted for rolling on horizontal rolling surfaces of unit tracks. At least two rows of inclined track fixing wheels which are linearly and symmetrically distributed and fixed on the axle housing are adopted for rolling on inclined rolling surfaces of the unit tracks, rigid unit tracks exceeding the length of one wheel are serially connected by a track threading chain to form a ring caterpillar track, and the unit tracks play a role of longitudinally dispersing the ground stress onto the supporting wheels. Therefore, the deformable wheels form an integral wheel relative to the ground. Under a rigid axle housing structure with certain radian, the entire deformable wheel assembly can climb over an obstacle on the ground by doing work only once.
Since the supporting wheels and the inclined track fixing wheels are simultaneously used in the patent of the deformable wheel, the inclined rolling surfaces need to be arranged on the unit tracks to allow the inclined track fixing wheels to roll thereon to fix the unit tracks, which has a comparatively complex structure. At the end of large-curvature revolution at the front and rear ends of a track-chain integrated-type caterpillar track, rigid back surfaces of the unit tracks cause fulminant impact on the flexible chain ring, causing very big noise whilst it is difficult to fixedly assemble and disassemble the supporting wheels on and disassemble it from the axle housing, which cause the production and the maintenance difficult.